As a rotary electric machine using a conventional slip ring device, for example, there is one as shown in FIG. 11. A turbine generator 1 serving as a rotary electric machine includes those broadly divided into a frame 2, a stator 3, a rotor 10, and a slip ring device portion 15.
The stator 3 has a stator core 4 wound by a stator coil 6 and is fixed to an inner peripheral portion of a frame 2. The rotor 10 has magnetic poles 12 concentrically wound by a rotor coil 13 and a directly coupled portion 14. A rotational shaft 11 of the rotor 10 is removably supported by respective bearings 7a, 8a in respective brackets 7, 8 attached to the frame 2.
Slip rings 18 are insulated and held in the vicinity of a shaft end portion extended in an end portion of the outside of the machine on the side opposite to the directly coupled side of the rotational shaft 11. A current collecting portion 16 of the slip ring device portion 15 includes the slip rings 18 and brushes 19 which come in contact with the periphery of the slip rings 18. The rotor coil 13 is connected to the slip rings 18 by connection conductors (both are not shown in the drawing) disposed in grooves on the periphery of the rotational shaft 11.
The current collecting portion 16 includes the slip rings 18, the brushes 19, brush holders 20, and an insulation protective plate 21. The slip rings 18 are made of alloy steel and are fitted on insulators 17 each formed in a ring shape on the vicinity of the shaft end portion extended in the end portion of the outside of the machine on the side opposite to the directly coupled side of the rotational shaft 11.
Furthermore, FIG. 12 and FIG. 13 show specific examples of a conventional slip ring structure, which is provided with a rotor shaft end portion 52 extended from a rotor shaft 51 to outside the machine. The rotor shaft end portion 52 is formed by machining from a structure integrated with the rotor shaft 51. Then, the rotor shaft end portion 52 and the rotor shaft 51 are formed with a hollow hole 53 which is formed in their central portions to the vicinity of a coil end.
The rotor shaft end portion 52 serves as an attaching portion of the slip ring structure. The rotor shaft end portion 52 is arranged with, for example, a first slip ring 54 on the positive pole side and a second slip ring 55 on the negative pole side. The first slip ring 54 is disposed on a first slip ring attaching portion 52a on the rotor shaft 51 side; and the second slip ring 55 is disposed on a second slip ring attaching portion 52b on the side opposite to the rotor shaft 51, that is, on the shaft end side of the rotor shaft end portion 52. As described above, the first slip ring 54 on the positive pole side and the second slip ring 55 on the negative pole side are needed.
The rotor shaft end portion 52 is formed with a lead connecting portion 56 between the first slip ring 54 and the second slip ring 55. The lead connecting portion 56 is formed with a first radial lead placing hole 58 in which a first radial lead 57 is placed and a second radial lead placing hole 60 in which a second radial lead 59 is placed.
A crescent shaped first axial lead 61 to be connected to the first radial lead 57 and a crescent shaped second axial lead 62 to be connected to the second radial lead 59 are attached by insertion in the hollow hole 53 which is formed in the central portions of the rotor shaft end portion 52 and the rotor shaft 51, the hollow hole 53 being formed to the vicinity of the coil end. Then, an insulator between leads 63 is inserted between the first axial lead 61 and the second axial lead 62; and an insulator 64 is inserted between the hollow hole 53 and the first axial lead 61 and between the hollow hole 53 and the second axial lead 62. An insulator 65 is provided at end portions of the first axial lead 61 and the second axial lead 62.
The first slip ring 54 is connected to the first radial lead 57 via a first slip ring lead 66 and the second slip ring 55 is connected to the second radial lead 59 via a second slip ring lead 67.
By the way, the supply of electricity from an external portion outside the machine and the extraction of electricity from the rotor to the external portion are the flow of the electricity as shown by arrows in FIG. 12. The supply of the electricity from the external portion outside the machine flows to the first slip ring 54 on the positive pole side via the brushes (not shown in the drawing). The electricity flown to the first slip ring 54 flows to the first radial lead 57 via the first slip ring lead 66. The electricity flown to the first radial lead 57 is supplied to the rotor coil via the first axial lead 61.
The extraction of the electricity from the rotor to the external portion flows from the rotor coil to the second axial lead 62. The electricity flown to the second axial lead 62 flows to the second radial lead 59. The electricity flown to the second radial lead 59 flows to the second slip ring 55 on the negative pole side via the second slip ring lead 67. The electricity flown to the second slip ring 55 is extracted to the external portion via the brushes (not shown in the drawing).    Patent Document 1: Japanese Unexamined Patent Publication No. 2003-164111    Patent Document 2: Japanese Unexamined Patent Publication No. H6-237558    Patent Document 3: Japanese Unexamined Patent Publication No. H8-242554    Patent Document 4: Japanese Unexamined Patent Publication No. H8-51765    Patent Document 5: Japanese Unexamined Patent Publication No. S59-216445    Patent Document 6: Japanese Unexamined Patent Publication No. S60-109744    Patent Document 7: Japanese Unexamined Utility Model Publication No. S59-176365